Respirator pumping apparatus



p 11, 1956 T. a HUXLEY m 2,762,200

RESPIRATOR PUMPING APPARATUS Filed June 24, 1952 5 Sheets-Sheet 1 INVENTOR T/IOMAS C. #uxumr.

(De-L ATTORNEYS Sept. 11, 1956 T. C. HUXLEY Ill RESPIRATOR PUMPING APPARATUS I Filed June 24, 1952 '5 Sheets-Sheet 2 INVENTOR.

BY 9 I ATTORNEYS Sept. 11, 1956 T. c. HUXLEY 111 2,762,200

RESPIRATOR PUMPING APPARATUS Filed June 24, 1952 I 5 Sheets-Sheet 5 Thur:

INVENTOR. Twnms Cf A z/xu' zl.

ATTORNEYS P 11, 1956 T. c. HUXLEY Ill 7 2,762,200

RESPIRATOR PUMPING APPARATUS Filed June 24, 1952 5 Sheets-Sheet 4 INVENTOR THOMAS C. AUXLEYH.

BYEMM ATTORNEYS United States Patent RESPIRATOR PUMPING APPARATUS Thomas C. Huxley III, Manhasset, N. Y., assignor to Conitech, Ltd., Bronx County, N. Y., a corporation of New York Application June 24, 1952, Serial No. 295,181

3 Claims. (Cl. 60-625) This invention relates to improvements in respirator pumping apparatus generally and, more particularly, to improvements in the pump and control unit for respirators.

One object of the present invention is the provision of a compact, readily-portable and reliable pump and control unit for artificial respirators.

Another object is to provide a pump and control unit wherein the pump, the actuating means therefor and the controls required for the proper operation of the pump in conjunction with the cuirass of the artificial respirator apparatus are all disposed within the casing of the apparatus.

Another object of the present invention is the provision, in a pump and control unit for respirators, of improved means for manually actuating the pump in the event of power failure, said manual means being effective to automatically disengage the power means from operative association with the pump when the manual means is operatively associated with the pump.

Another object of the present invention is the provision, in a pump and control unit for respirators, of an improved cranking arrangement for actuating the pump in the event of power failure, the power means for actuating the pump being automatically declutched from operative association with the pump in response to the operative association with the pump of a hand crank.

Another object of the present invention is the provision, in a pump and control unit for respirators, of an improved control arrangement for controlling the admission of air to the pumping chamber during the suction phase of the pumping cycle and for independently controlling the discharge of air from the pumping chamber during the positive pressure phase of the pumping cycle.

Another object of the present invention is the provision, in a pump and control unit for respirators, of an improved control arrangement of the above character in'which there is provided additional safety means to limit the amount of negative pressure produced by the pump and applied to a cuirass operatively connected to the pump.

Yet another object of the present invention is the provision of a generally improved pump and control unit for respirators which is simple in design and construction, relatively inexpensive to manufacture, and highly effective in the accomplishment of its intended purpose.

The above and other objects, features and advantages of the present invention will be more fully understood from the following description considered in connection with the accompanying illustrative drawings.

In the drawings:

Fig. 1 is a top plan view of the respirator pumping apparatus according to the present invention;

Fig. 2 is a partial sectional view taken on the line 22 of Fig. 1;

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 2;

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 1;

ice

Fig. 5 is a sectional view taken on the line 5-5 of Fig. 1;

Fig. 6 is a sectional view taken on the line 66 of Fig. 1;

Fig. 7 is a sectional view taken on the line 7-7 of Fig. 2;

Fig. 8 is a perspective view of the vacuum control member;

Fig. 9 is a perspective view of the respirator pumping apparatus shown connected to a cuirass;

Fig. 10 is a sectional view taken on the line 1010 of Fig. 3 with the crank shown disengaged from the apparatus;

Fig. 11 is a fragmentary view similar to Fig. 10 showing the crank engaged in the apparatus;

Fig. 12 is a sectional view taken on the line 1212 of Fig. 10; and

Fig. 13 is a sectional view on an enlarged scale, taken on the line 13-13 of Fig. 1 with a conduit shown connected to the pumping apparatus.

Referring to the drawings and, more particularly, to Fig. 9 thereof, the respirator pumping apparatus 10 is adapted to periodically supply air to and withdraw air from a cuirass 12, which is operatively connected to the pumping apparatus 10 by means of the conduit 14. The cuirass 12 may be any one of the well known types, for example the type shown and described in the patent to Thomas C. Huxley III, No. 2,466,108, issued April 5, 1949, for Artificial Respirator. It will be understood that the cuirass 12 is adapted to be fitted to a patient, and when so fitted, the pumping apparatus 10 is adapted to periodically supply air to and withdraw air from said cuirass to simulate normal respiration. Thus the pumping apparatus 10, when operatively associated with the cuirass 12, alternates between partial evacuation and normal pressure of the air within the cuirass at a controlled and variable rate to successfully simulate normal respiration.

The apparatus 10 comprises a bellows-type pump 16 which has means integrated therewith for controlling the amount of negative pressure or suction applied to the cuirass 12 and for controlling the amount of positive pressure applied to said cuirass. The pumping apparatus 10 is housed in a suitable casing 18, the latter having casters 20 at its lower end to facilitate the movement of the apparatus 10 on a supporting surface. The pump 16, which is preferably of the bellows-type, comprises a fixed head 22 and a piston 24 relatively movable thereto, said piston being mounted for reciprocation by the means to be described in detail hereinafter. The pump 16 is of generally rectangular outline to conform to the general cross-sectional outline of the casing 18. The pump head 22 is fixed to the casing 18 in any suitable manner, as by means of the flange 26 secured between the brackets 28 and 30, the latter being secured to the casing in any desired manner. The piston 24 is formed complementary to the pump head 22 and is provided with a peripheral outwardly extending flange 32, the latter having secured thereto one end 34 of the bellows 36 in any conventional manner, as by means of the rivets 38. The opposite end 40 of the bellows 36 is secured to the underside of the head 22 in a similar manner as the securement of the end 34 of said bellows to the piston 24. It will be understood that the bellows 36 is secured to the pump head 22 and piston 24 in sealing relation therewith whereby there is defined between said head and piston a sealed pumping chamber 42. The'bellows 36 is provided with a series of peripherally extending fold retaining members 44 and 46, said members conforming to the cross-sectional outline of the pump 16 and being effective to maintain the bellows folds, as shown in Fig. 2. It will also be noted that the fold retaining members 44 are 7 ,ag'reaaoo V a A g laterallyspaced outwardly of; the fold retaining members 46 and that the latter are of circular cross-section, whereas the members 44 are of elongated cross-section.

The piston 24 has a depending shaft 48 positioned V centrally.thereof, said shaft .beingaperturedat 50 for hollow shaftjSS the bearing sleeve 52, 'disposed on" the interior of'the shaft 48, being slidably mounted orisaid hollow shaft. 7 .The hollow shaft, 58, extends vertically of the casing 18 and is,secured'centrally therein by any suitable means, for examplegbylsupportingbrackets 60 I and 62 at the lower and upper .ends'of s aid casing,re-

spectively. Thus the piston 24 is guided for its range of reciprocation by meansofthc hollow shaft 58, the bearing sleeve 52 of said pistonbeingslidably mounted on said hollow shaft; Laterally projecting from the shaft 48, and in fixed relation therewith, is a pin member 64 which is journaled for relative rotation in the bearing 66' at the upper end ofthe connecting rod 68. As shown in Fig. 3, the connecting rod 68 is I shaped in cross-section arid has a bearing .70, similar to bearing 66, at its'lower end for the reception of the crank pin 72, the latter being journaled for rotation in the connecting-rodfis by means of the bearing .70. Thecrank pin 72 is secured to the crank'arm 74 in any suitable .manner whereby it will be seen that the rotation or oscillation .of said crank arm will be elfective to reciprocate theconnecting rod68 and the latter will impart its rcciprocatory motion to the piston 24. Thus the rotation oroscillation of the crank arm 74 will'be effective to correspondingly control tliepurnping action of the piston 24, the down stroke of the latter being the negative pressure or suction stroke and the up stroke being-the positive pressure stroke of the apparatus. It will be understood that the volume of the pumping chamber '42 will vary froma maximum to Ia rninimurn' as the piston 24 is reciprocated through a ,cycle. of

7 generally conventional construction and is adaptedto reduce' the speed ofshaft 76 relative tothe speed of shaft 32 which constitutes the input shaft of said speed reducer. Shaft 82, during the normal operation of the apparatus 10, is adapted to be power driven by means of motor 84 in a manner now to be described. The 'outputshaft 86 of the motor 84 is provided with a split pulley 8 8, the movable half 90 of the pulley 88 being spring biasedtowards the fixed half 92 of said pulley by means-oflthe compression spring 94. More particularly; oneend 96 of the spring 94 abuts the bearing'plateQS secured to the shaft 86, and the opposite end 100 of. the spring 94 abuts the movable half 90 of the pulley 88 yvhereby themovable half 90 of said pulley is spring. biased toward the fixed half 92 of said pulley The pulley 102 fixed to. the input shaft 82 of the speed reducer. 80 is also of the split type, the. movable half 104 of which rnay be adjusted relative to the fixed half 106 by means of the speed adjustment device 108, which is accessibleexternally Y? h S eed i j tii 'sc afive, m hespeea of,shaft-- V 86, as will be readily apparent. Thus to increase the speed of shaft 82 relative to shaft 86, the speed adjustment device 108 will be rotated in a direction to move the half 104 of the pulley 102 away from the fixed half 106 of said pulley whereby the drive belt 110 will be automatically adjusted toa position axially closer to.

the shaft 82.

' It will be understood that as the halves of the pulley 102 are,separated, thehalves of the pulley 83 come closer t gethen'the position of the'halves of the latter pulley being maintained byTthe spring 94; described above.

The speed control7devicej108,'lhavingthe control knob 109, thus controls the speed of rotation of the shaft 82 of the speed reducer till for the adjustment of the proper pumpingrate', said pumping rate being indicated on the instrument panelI118-ofthe apparatus; as will be more fully described hereinafter. The relative speed of rotation of shafts 82 and 76 of the speed reducer 80 is fixed whereby it will be apparent that the speedadjustment device 108will be effective tova ry therate of reciprocation ofithe piston 24 within a predeterminedrange- 'l'he speed reducer 80 is secured in the casing 13 in the bottom region thereof inany suitable manner, vas bymounting said speed reducer on the. plate 112.. A take-off shaft.

number of respirations per minute will be under the cone trol of the speed adjustmentdevice 108.

V In the normaloperation of the apparatus 10 the motor. 84 will be utilized as the power source for reciprocating the piston'24, land in the event of power failurethere is'.

provided alternate'rnanually operated means 'for reciprocating 'said piston. Z The alternate manually operated" I means comprises acr'ank120having a handle 122 and p a laterally projecting s haft 124, the latter, when operatively associated withjthe apparatus'10, being adapted to automatically declutchth e speed reducer from the shaft 76. "Thus when crank is operatively connected to 'the apparatus 10', the train of gears disposed in the speed reducer SiI are d'eclutch ed from output shaft76 of said speed r'educer'fwhereby to permit, and facilitate the ease of manual oscillation ofthe crank arm 74. With reference to Fig. l 0,- the shaft 76 of speed reducer 80 has a shaftportion 76' which is apertured at 128, the latter beingladapted for the'reception of theportion 124 of the crank 120. The shaft portion 76 has a longitudinal key secured therein by means of the'scr eWiBZJand the portion 124. of the crank 120 has a keyway 134 formed complementary to the key 130 whereby thepor'tion 124 may beinserted in the'aperture 128 in only one'po sition, 521d pos tion being preselected for optimum ease in manually oscillating the crank'120 The aperture or bore 128, lwhichconstitutes anlextension of aperture or here 128 has positionedthereina plunger. 136, the latter being spnng drrven outwardly of said aperture 123 by means of the compression spring 138 seated in the end of said 7 V aperturef The .plunger-13'6 has a transversely extending member .142 secured thereto by means of the pin 1144, said member having integrally formed therewith )dia metrically opposed end pin elements'f146 which' are adapted for a purposewhich' will be described in detail hereinafter. 1 i a i Whenthe. piston 24 is power driven by means of the. motor 84, the gear1'48 disposed in reducer 80 is drivin gly connected to the shaft 76, the gear 148 having its hub 149 keyed. to .the intermediate shaft150 by means of the key or pin 152. With reference to Figs. 10, 11 and 12 of pin elements 146 when said slots are aligned as shown in Fig. 12. The plunger 136 is adapted to be axially movable between the power driven position as indicated in Figs. and 12 and the manually driven position as indicated in Fig. 11, the shafts 150 and 76 being fixed against relative rotation in the power driven position of plunger 136 by means of pin elements 146 and being free for relative rotation in the manually driven position of said plunger, as in the latter position pin elements 146 will be retracted from slot 155. Thus in the manually driven position of plunger 136 the pin elements 146 will clear the end 157 of shaft 150 whereby the latter will be free for rotation relative to shaft 76. For manually oscillating the shaft 76 for actuating piston 24, the portion 124 of crank 120 is inserted in the aperture 128, said portion 124 axially displacing plunger 136 towards the crank arm 74 against the biasing of the spring 138 as shown in Fig. 11, the axial movement of the plunger 136 being efiective to disengage the pin elements 146 of the member 142 from the intermediate shaft 150.

From the above it will be apparent that, when the apparatus is power driven, gear 148 will drive shaft 76 since said gear is keyed to shaft 150 and the latter is keyed to shaft 76 by means of the pin elements 146, and when the apparatus is manually driven gear 148 and shaft 150 will be disengaged from driving relation with shaft 76 through the retraction of pin elements 146 from the shaft 150. When the crank 120 is inserted in the aperture 128, the axial movement of the plunger 136 to the manually driven position will be effective to disengage the pin elements 146 from their associated slots 155 whereby the gear 148 will be disengaged from the shaft 76. Accordingly, the axial position of the plunger 136 controls the driving engagement of the gear 148 with the shaft 76 and the insertion of the portion 124 of the crank 120 in aperture 128 is automatically effective to displace the plunger 136 from its power driven position to its manually driven position whereby to disengage the gear train in the speed reducer 80 from driving relation with piston 24. The plunger 136 has an annular groove 156 adjacent its outer end which has seated therein a suitable oil seal 158. The shaft portion 76' of shaft 76 has an annular recess 147 adjacent its outer end for the reception of the snap ring 159 of crank 120 when the latter is engaged in aperture 128. Shaft 76 is journaled for rotation in the bearing plate 160, the bushing 162, and shaft 150, said bearing plate being secured to the housing 164 of the speed reducer 80 in any suitable manner as by means of the screws 166.

In order to control the amount of vacuum or negative pressure applied to the cuirass 12 by the pump 16, there is provided a vacuum control for said pump, said vacuum control comprising a control member 170 which is adapted to control the admission of air to the chamber 42 on the down stroke of the piston 24 (see Figs. 2, 7 and 8). More particularly, the vacuum control member 170 is mounted for rotation relative to the panel 118, said member having an actuating shaft 172 projecting outwardly of said panel. Secured to the upper end of shaft 172, externally of the housing 18, is a control knob 174, said knob being secured to the shaft 172, in any desired manner, for example by means of the set screw 176. The member 170 has an annular shoulder 178 which is in abutting relation with the shoulder 180 of the bracket part 62, said shoulder 178 being biased in said abutting relation with shoulder 180 by means of spring 182. The bracket part 62 and consequently the shoulder 180 thereof is fixed in the casing 18 and the shoulder 178 of the member 170 is adapted to rotate relative to said part 62. The valve member 170 has an arcuate face 184 at one side, said face in conjunction with port 171 being adapted to control the admission of air to the conduit 186 which communicates with the interior of the pumping chamber 42. It will be understood that the conduit 186 is in communication with the port 188, the latter communicating with the interior of the pumping chamber 42. It will be evident from the above that the angular position of the arcuate face 184 of the vacuum control member relative to the inlet port 171 to the conduit 186 will determine the amount of air that may be admitted to the pumping chamber 42 during the negative pressure or vacuum phase of the pumping cycle. the vacuum control member 184 is shown in a slightly open condition and the'rotation of said control member in the direction of the arrow V, as shown in said figure, will be effective to increase the amount of air admitted to the pumping chamber 42. Thus the arcuate face 184 of the member 170 cooperates with inlet port 171 tothe conduit 186 to control the amount of air admitted to the pumping chamber. As previously noted, the upright shaft 58 is hollow and the lower end portion of said shaft is provided with vertically spaced annular series of vents 190, the latter communicating with the interior of the casing 18 and consequently with the surrounding atmosphere of the apparatus 10, it being understood that substantial air leakage through said casing is inherent in the construction thereof. The lower end of the hollow shaft 58 has a reinforcing tube 192 mounted thereon coaxially therewith, said reinforcing tube having vents 191 in registry with the vents 190 above referred to. Thus the control member 170 is effective to control the admission of air to the pumping chamber 42, the path of air being. from the atmosphere through the vents 191 and 190, past the valve member 170, through the conduit 186 and port 188. The opening of the port 171 of the conduit 186 under the control of the valve member 170 increases the amount of air admitted to the pumping chamber 42 and consequently decreases the negative pressure or vacuum applied to the interior of the cuirass 12. From the above, it will be apparent that the rotation of the vacuum control member 170 will be effective to control the amount of vacuum or negative pressure applied to the cuirass, the amount of vacuum or negative pressure supplied by the pump 16 being independent of the amount of positive pressure, if any, applied to the :cuirass 12 by said pump.

In most cases the application of positive pressure to the interior of the cuirass 12 is unnecessary, however when desired, the amount of positive pressure can be controlled through the pressure control valve 200 now to be described in detail. (See Figs. 1 and 4.) The pressure control valve 200 comprises an actuating shaft 202 having a pressure control knob 204 secured thereto at one end by means of the set screw 206, said actuating shaft 202 being journaled for rotation in the plate 208. The shaft 202 has a collar 210 formed integral therewith, said collar being adapted to cooperate with adjacent portions of the plate 208 for the positioning of shaft 202. The shaft 202 has an enlarged portion 212 at its lower end which is externally threaded, as indicated at 214, said enlarged threaded portion being adapted to cooperate with the short tubular member 216 which is internally threaded at its upper end complementary to the threads 214. The member 216 is provided with diametrically opposed flattened portions 218 which are adapted to have cooperatively associated therewith the legs 220 of the clip member 222. The base 224 of the clip member 222 is secured to the underside of plate 208 in any desired manner, the spaced legs 220 of said clip member being adapted to restrain the tubular member 216 against rotation, the latter being free for axial movement relative to the portion 212. It will be apparent from the above that the rotation of shaft 202 will be effective to axially displace the tubular member 216 a corresponding amount. The shaft portion 212 is centrally apertured at 226 for the reception of the guide shaft 228 which is freely movable in said aperture. The ,guide shaft 228 has a valve member or diaphragm 230 secured at its lower end, said diaphragm 230 being adapted to control the amount of air bypassed during the positive With reference to Fig. 7,-

' maximum negative pressure condition.

pressure phase of the pumping cycle. The lower end 232. of the'tubula'r member 216 :is adapted to cooperate with.

j sfi l s f q tion o he d aph a 123 to controlthe bypass; of air for thereby contrqlling. the amount of positive pressure pumped by the 'b'ellowsfp'ump 161 Thus the more the tubular member216is positioned away froin head 22; the greater will'be' theamount ofai'r bypassed through 'saidihead, and if 'desiredithe'diaphragm 230 'maybe' retained closed 'onthe head 22 by rotating under the controlof the pressure valve'200, the greater the amount of air so bypassed, thelower will be the positive pressure'applied to the cuirass; Thus the amount of air bypassed in this manner'is under the control of the actuator shaft 202 and associated mechanisnnithe latter being eifective to axially position thetubular member 216 relative to the diaphragm 230. During the suction or negative pressure phase of thespuniping fcyc'le the .diaphragm 23% Will be closed to the head- 22 .by the atmosphere pressure which will be'greater than the pressure'in the pumping chamber 42; "From the above, it will be apparent that the positive pressure control valve 200 isin-dependent of the aforedescribed vacuum control 174}.

.The positive pressure control knob 204 is'acce'ssible ex 7 ternally of the apparatus at the panel 118 and is positioned closely adjacent to the vacuum control knob 174 to facili tate the ease of control of the apparatus 10( l a In order to limit the aniount of negative pressure or vacuum produced by thep'ump 16; there is provideda V relief valve 240 which'is'integrated'with the piston 24 in a manner now to be described (see Figs. 2 and 5 The piston 24 is ported at'242, the latter being open to the interior of the casing 18 in the open condition of valve 246 and said port is normally closedbythe valve member or'diaphragm 244; Surrounding-the port 242 and depending from the piston 24 is avalve body member 246 having a shoulder 248 forming a platform for adjacent portions of the valve member 244.1 The valve member 244 is secured to one end of the shaft 250, said shaft being adjustably secured'to the'flexible plate 252,- theilat ter having peripheral portions secured to the valve body,

member 246 in any desired manner. The valve member. 244 and plate 252 are maintained in a fixed spaced relation by means of the nut'254which is threaded on the shaft 250, The 'plate 252 is formedof a flexible resilient material such as spring metal and is adapted to flexibly yield to permit the valve 244 to open at a predetermined Thus theplate 252 controls the valve member 244 and is preset to yield and permit said valve member to open at a predetermined maximum negative pressure condition. It will be apparent that the amount of negative pressure or suction necessary to'open the member 244 may be adjusted under the control of the axial position of the nut 254, the closer said nut is positioned to the valve member 244, .the greater the amount of negative pressure or suctionbeing required for opening said valve'mcmber. mary purposejof the relief valve 240 is to vent excess negative pressures which may inadvertently or accidentally occur in the apparatus andunder normal operating conditions the valve member 244 will be seated ontheshoulder 2480f the valve body 246. 1

Thus the priln'case of power failure, air'leakage, or any'condition which signifies improper air'flow to the patient, 'analarm system 259 will be actuated. Thesafety alarm comprises a casing 261} (see Fig. 2) which has a port 262 in com-' munication with the port 264 in the head 22 by means of the short conduit 266; In the case of improper air flow to the patient through the medium of cuirass 12,

the, safety alarm 259 will. beiactnatedstor ing a. suitable hell. (not shown); The safety ha 259gisundenthej s b n ala m. s it h 8 the l lbs s ured". in the panel 118 and readily accessible at the 'top'of' the apparatus. The instrument pa nel;118 is further provided with a Powe w t 27 w h is sQnnsct d t tan em trols'the electricalcircuit for the motori84; Aslpreviouslyl; described in detail, in'case of power failure' thelfpurnp 16 rn'ay'be rea-dily actuatedby means of'the eranki12't), the

latter being efiective to automatically disconnect the gear] 7 train disposed in geanreducer fromidrrvlng relat on with said pump.

With reference to Figs. 1, 6 and'l3, there' is'providedl in'the'ins'trument panel'llS, atithe topot theapparatus,

a 'port 272 which communicates with the interror'of pumping chamber 42. Thelport'272 is defined'by short conduit 274 which is adapted to frictionallyreceive the end 276 of the conduit :14 to thereby'connectthej cuirass 12 with the interiorof the pumping chamber 42. The conduit 274 has one end secured to the head22,.at' 'port 275 in said head, by means of flange '27'7,1theopp'osite end of said conduit'be ingjsecured to the panel'1 1 8 in .any desired manner.

tached to, and removable from, the interior ;of"conduit 274. The port 272 'at'panel 118', defined bycondult 274,

is normally closed to the atmospherewhen theiconduitll' is disconnected from the apparatus 19: For this'purpose there'is'provided a cover member 280 havingia'pairof spaced lugs 232 which area'pertured at 284'forthe'reception of the end convolutions 286 of the coil springJZQSQ the latter being positioned. in the U shaped. tube 290 haviing its ends 29l'secur'ed to pan'el'llS. Itwillbereadily'f apparent from the above that thejcovermemberi280j be spring urgedby means of the spring 288lin a closing direction and that said' cover member may be readily opened against'the spring biasing of said' spring forthe connection of the end 276' of the conduit 14to the coni duit 274. Thus the spring 283, which hasitsendjcon volution 236 extending through the apertures 284ofthe" cover member 280, provides a' ready means' for springhingedly mounting said cov'ermember onthe panel 1 18;

' When the conduit 14 is secured to the apparatus inithe manner described above, the cover member '28il willbe spring urged against said conduit'as shown'in 'Eig." 13.f

While I have shown and describedthe pr'eferr'edjem bodiments of my invention, it will be understoodfthat',

various changes may 'be made" in the present-invention without departing from the underlyingidea or principles" of the invention within the; scope of theapperidedelainis.

Having thus described my invention, What I -claim and desireto secure by Letters Patent, is:

l. Respirator pumping apparatus adapted to inducea rhythmtic flow of air to and from the'cuirass of artificial respirator apparatus,- comprising a 'pump 'having' atfixed head and a movable piston defining anexpansibleiand.

contractible air chamber having an outlet adaptedfto be connected to said-cuirass in fluid-flow relation thereto; means for actuating-said-movablepiston for cyclically fixed hollow shaft'for guiding'the movementof said piston, the interior of said guideshaftcommunicaiting with said one port underthe control of said first valve. means and being vented' to the atmosphere wherebysaid first valve means controls the venting ofjsaid"oneport' through said guide shaft.

The end 276 of conduit 14 is" retained in position relative to the conduit 274 by a t e tion-fit, the end 276 ofthe conduit 14'b'e1ng readtlyat-f 2 Respirator pumping apparatus adapted to induce a rhymthic flow of air to and from the cuirass of artificial respirator apparatus, comprising a pump having a fixed head and a movable piston defining an expansible and contractible air chamber having an outlet port adapted to be connected to said cuirass in fluid-flow relation thereto, means for actuating said movable piston for cyclically expanding and contracting said chamber for inducing a rhymthic flow of air to and from said chamber through the outlet port thereof, and fluid-control means independent of said outlet port for limiting the maximum and minimum air pressures, respectively, in said chamber in the contracted and expanded conditions, respectively, thereof whereby to control the maximum and minimum cyclic air pressures flowing through said outlet port, said fluid-control means including a second port in communication with the ambient atmosphere, and a manually operable valve for regulating the flow of air into and out of said chamber through said second port during the expansion and contraction of said chamber, and a third port in communication with said chamber and the ambient atmosphere for preventing the generation in said chamber of air pressures above a predetermined maximum, said third port having a manually operable valve for regulating the flow of air therethrough.

3. Rerspirator pumping apparatus adapted to induce a rhymtbic flow of air to and from the cuirass of artificial respirator apparatus, comprising a casing having a pump mounted therein, said pump having a fixed head and a movable piston defining an expansible and contractible air chamber having an outlet port adapted to be connected to said cuirass in fluid-flow relation thereto, means for actuating said movable piston for cyclically expanding and contracting said chamber for inducing a rhymthic flow of air to and from said chamber through the outlet port thereof, and fluid-control means independent of said outlet port for limiting the maximum and minimum air pressures, respectively, in said chamber in the contracted and expanded conditions, respectively, thereof whereby to control the maximum and minimum cyclic air pressures flowing through said outlet port, said fluid-control means including a second port in communication with the ambient atmosphere, and a manually operable valve for regulating the flow of air into and out of said chamber through said second port during the expansion and contraction of said chamber, and a third port in communication with said chamber and the ambient atmosphere for preventing the generation in said chamber of air pressures above a predetermined maximum, said third port having a manually operable valve for regulating the flow of air therethrough, an instrument panel disposed at the top of said casing in laterally spaced relation to said fixed head, said instrument panel having negative and positive pressure control knobs accessible thereat for manually controlling said second and third port valves, respectively, at said instrument panel.

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